--  @testpoint:opengauss关键字clean(非保留)，作为函数名
--关键字不带引号-成功
drop function if exists clean;
create function clean(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function clean;

--关键字带双引号-成功
drop function if exists "clean";
create function "clean"(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function "clean";

--关键字带单引号-合理报错
drop function if exists 'clean';
create function 'clean'(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/

--关键字带反引号-合理报错
drop function if exists `clean`;
create function `clean`(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/